procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

re PR tree-optimization/33563 (DSE removes non-dead store)

Browse source 
2007-09-26  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/33563
	* tree-ssa-dse.c (get_use_of_stmt_lhs): Rename to ...
	(get_kill_of_stmt_lhs): ... this.  Re-structure.  Handle
	aggregate stores.
	(dse_optimize_stmt): Call get_kill_of_stmt_lhs instead of
	get_use_of_stmt_lhs.

	* gcc.dg/torture/pr33563.c: New testcase.

From-SVN: r128815
This commit is contained in:
Richard Guenther 2007-09-26 15:31:50 +00:00 • committed by Richard Biener
parent 68b72a4465
commit e2e79a188a
4 changed files with 82 additions and 47 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
gcc/ChangeLog
View file

@ -1,3 +1,12 @@
2007-09-26 Richard Guenther <rguenther@suse.de>
PR tree-optimization/33563
* tree-ssa-dse.c (get_use_of_stmt_lhs): Rename to ...
(get_kill_of_stmt_lhs): ... this. Re-structure. Handle
aggregate stores.
(dse_optimize_stmt): Call get_kill_of_stmt_lhs instead of
get_use_of_stmt_lhs.
2007-09-26 Joseph Myers <joseph@codesourcery.com>
PR c/25309

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2007-09-26 Richard Guenther <rguenther@suse.de>
PR tree-optimization/33563
* gcc.dg/torture/pr33563.c: New testcase.
2007-09-26 Joseph Myers <joseph@codesourcery.com>
PR c/25309

22
gcc/testsuite/gcc.dg/torture/pr33563.c Normal file
View file

@ -0,0 +1,22 @@
/* { dg-do run } */
/* { dg-options "--param max-aliased-vops=0" } */
struct T
{
int a, b;
} t, q;
int main (void)
{
struct T *p;
t.a = 1;
t.b = 2;
q = t;
t.a = 3;
if (q.a != 1)
__builtin_abort ();
return 0;
}

93
gcc/tree-ssa-dse.c
View file

@ -210,62 +210,62 @@ memory_address_same (tree store1, tree store2)
== NULL);
}
/* Return the use stmt for the lhs of STMT following the virtual
def-use chains. Returns the MODIFY_EXPR stmt which lhs is equal to
the lhs of STMT or NULL_TREE if no such stmt can be found. */
static tree
get_use_of_stmt_lhs (tree stmt,
use_operand_p * first_use_p,
use_operand_p * use_p, tree * use_stmt)
{
tree usevar, lhs;
def_operand_p def_p;
/* Return true if there is a stmt that kills the lhs of STMT and is in the
virtual def-use chain of STMT without a use inbetween the kill and STMT.
Returns false if no such stmt is found.
*FIRST_USE_P is set to the first use of the single virtual def of
STMT. *USE_P is set to the vop killed by *USE_STMT. */
if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
return NULL_TREE;
static bool
get_kill_of_stmt_lhs (tree stmt,
use_operand_p * first_use_p,
use_operand_p * use_p, tree * use_stmt)
{
tree lhs;
gcc_assert (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT);
lhs = GIMPLE_STMT_OPERAND (stmt, 0);
/* The stmt must have a single VDEF. */
def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_VDEF);
if (def_p == NULL_DEF_OPERAND_P)
return NULL_TREE;
if (!has_single_use (DEF_FROM_PTR (def_p)))
return NULL_TREE;
/* Get the immediate use of the def. */
single_imm_use (DEF_FROM_PTR (def_p), use_p, use_stmt);
gcc_assert (*use_p != NULL_USE_OPERAND_P);
first_use_p = use_p;
/* If the use is not simple, give up. */
if (TREE_CODE (*use_stmt) != GIMPLE_MODIFY_STMT
|| get_call_expr_in (*use_stmt))
return NULL_TREE;
/* We now walk the chain of single uses of the single VDEFs.
We succeeded finding a kill if the lhs of the use stmt is
equal to the original lhs. We can keep walking to the next
use if there are no possible uses of the original lhs in
the stmt. */
do
{
/* Look at the use stmt and see if it's LHS matches
stmt's lhs SSA_NAME. */
def_p = SINGLE_SSA_DEF_OPERAND (*use_stmt, SSA_OP_VDEF);
tree use_lhs, use_rhs;
def_operand_p def_p;
/* The stmt must have a single VDEF. */
def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_VDEF);
if (def_p == NULL_DEF_OPERAND_P)
return NULL_TREE;
return false;
usevar = GIMPLE_STMT_OPERAND (*use_stmt, 0);
if (operand_equal_p (usevar, lhs, 0))
return *use_stmt;
/* Get the single immediate use of the def. */
if (!single_imm_use (DEF_FROM_PTR (def_p), first_use_p, &stmt))
return false;
first_use_p = use_p;
if (!has_single_use (DEF_FROM_PTR (def_p)))
return NULL_TREE;
single_imm_use (DEF_FROM_PTR (def_p), use_p, use_stmt);
gcc_assert (*use_p != NULL_USE_OPERAND_P);
if (TREE_CODE (*use_stmt) != GIMPLE_MODIFY_STMT
|| get_call_expr_in (*use_stmt))
return NULL_TREE;
/* If there are possible hidden uses, give up. */
if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
return false;
use_rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (TREE_CODE (use_rhs) == CALL_EXPR
|| (!is_gimple_min_invariant (use_rhs)
&& TREE_CODE (use_rhs) != SSA_NAME))
return false;
/* If the use stmts lhs matches the original lhs we have
found the kill, otherwise continue walking. */
use_lhs = GIMPLE_STMT_OPERAND (stmt, 0);
if (operand_equal_p (use_lhs, lhs, 0))
{
*use_stmt = stmt;
return true;
}
}
while (1);
return NULL_TREE;
}
/* A helper of dse_optimize_stmt.
@ -448,8 +448,7 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
the stores are not to the same memory location then walk the
virtual def-use chain to get the stmt which stores to that same
memory location. */
if (get_use_of_stmt_lhs (stmt, &first_use_p, &use_p, &use_stmt) ==
NULL_TREE)
if (!get_kill_of_stmt_lhs (stmt, &first_use_p, &use_p, &use_stmt))
{
record_voperand_set (dse_gd->stores, &bd->stores, ann->uid);
return;